In the past, people always use the hand tool by feeling, there is no data to make sure the power while using the hand tool is suitable or not. It always causes over-power or insufficient-power and that will damage the safety. For example, the wrench provides torsion power for different purpose of use. While using the wrench for the purpose of tightening a fastener, different people use different power to produce different torsion values to tighten. So the tightening force of the fastener will be totally different.
U.S. Pat. No. 6,968,759 discloses the typical electronic torque wrench comprising inner and outer telescoping housing portions and a battery tray assembly telescopically receivable in the inner housing portion and a bezel assembly receivable in an aperture in the outer housing portion and interconnected with the housing portions and the battery support assembly by a single fastener. The bezel assembly carries torque measuring circuitry including a microcontroller, and a four-key pad including arrow keys for incrementing and decrementing a preset torque level at any time, an on/zero key and a units key for toggling among plural different units of torque measurement. The preset torque level is displayed until torque is applied or a key is pressed and can be changed and displayed at anytime.
However, those prior arts providing the display of torsion value, but with technology developing, the need of functions of the electronic torque wrench is also increasing, so that using the space inside of the electronic wrench efficiently is more important; especially the length of electronic wrench is limited by the size of the working place, the width of electronic wrench is limited by the size of people's hand. So the electronic mechanism only can be installed in the depth of the electronic wrench. Thus there is an eager demand for a novel design which can improve the defect in the prior art.